The disclosure relates to a power storage control apparatus.
Japanese Patent Application Publication No. 2013-138530 discloses that a battery is added to an existing solar photovoltaic system so that excess power may be stored in the battery. FIG. 1 illustrates a power storage control apparatus of a related art. Charging of a battery requires DC voltage. Thus, to add a battery to a solar photovoltaic system, battery 20 is typically connected through bidirectional DC-DC converter 40 to power line 35 connecting solar photovoltaic (PV) module 30 and PCS 32, as schematically depicted in FIG. 1.
In the system illustrated in FIG. 1, a controller (omitted from FIG. 1) for bidirectional DC-DC converter 40 (also referred to as converter 40 hereinbelow) may perform control as follows:
While PV module 30 is generating power, the controller controls converter 40 so that a certain amount of power may be inputted to the PCS 32 (or in other words, so that a certain portion of the power generated by PV module 30 may be supplied to PCS 32 and the rest may be stored in battery 20).
While PV module 30 is not generating power, the controller controls converter 40 so that an input voltage for PCS 32 may be maintained at a predetermined voltage.
In other words, the controller may perform a constant current control on converter 40 while PV module 30 is generating power, and perform a constant voltage control on converter 40 while PV module 30 is not generating power. By such control of converter 40, excess power of the power generated by PV module 30 can be stored in battery 20 (e.g., when power generated by PV module 30 is more than the power consumed by load 44), and while PV module 30 is not generating power, the power stored in battery 20 can be supplied to load 44 either solely or together with power from grid 42. Thus, the above-described control enables effective use of the power generation capacity of PV module 30.